The remote host is missing an update to the system as announced in the referenced advisory FreeBSD-SA-07:06.tcpdump.asc

Upgrade your system to the appropriate stable release or security branch dated after the correction date https://secure1.securityspace.com/smysecure/catid.html?in=FreeBSD-SA-07:06.tcpdump.asc

Tcpdump is a commonly used network diagnostic utility which decodes packets received on the wire into human readable format. An un-checked return value in the BGP dissector code can result in an integer overflow. This value is used in subsequent buffer management operations, resulting in a stack based buffer overflow under certain circumstances.